Question: Simplify the following expression: $z = \dfrac{4a - 9}{5} \div \dfrac{7a}{8}$
Explanation: Dividing by an expression is the same as multiplying by its inverse. $z = \dfrac{4a - 9}{5} \times \dfrac{8}{7a}$ When multiplying fractions, we multiply the numerators and the denominators. $z = \dfrac{ (4a - 9) \times 8 } { 5 \times 7a}$ $z = \dfrac{32a - 72}{35a}$